skill-check
Validate Claude Code skills against the agentskills specification. Catches structural, semantic, and naming issues before users do.
Best for Skill authors and maintaine…Works with GitHubLow risk
⌘source
- author
@sickn33- language
- Python
★34kstars
5.6kforks
Apr 18, 2026
✦overview.md
Key Features
- ·Validates SKILL.md files against agentskills specification
- ·Catches structural errors and semantic contradictions
- ·Identifies naming anti-patterns and quality gaps
- ·Performs read-only validation in a single pass
- ·Free tier with basic validation checks
Use Cases
- →Reviewing a skill before publishing to a marketplace
- →Debugging why a skill doesn't trigger correctly
- →Onboarding a team to skill authoring standards
- →Validating SKILL.md files when users request skill checks
Best for
- ✓Skill authors and maintainers
- ✓Marketplace quality assurance
- ✓Team skill development workflows
Not ideal for
- !Anti-slop detection
- !Security scanning
- !Token analysis
FAQs
name
skill-check
description
Validate Claude Code skills against the agentskills specification. Catches structural, semantic, and naming issues before users do.
license
MIT
category:development
risk:safe
source:https://github.com/olgasafonova/SkillCheck-Free
date_added:2026-03-11
author:olgasafonova
tags:["validation","linter","agentskills","skill-authoring","code-quality"]
tools:["claude","cursor","windsurf","codex-cli"]
allowed-tools:Read Glob
compatibility:claude-code
SkillCheck
Overview
Validate SKILL.md files against the agentskills specification and Anthropic best practices. Catches structural errors, semantic contradictions, naming anti-patterns, and quality gaps in a single read-only pass.
When to Use This Skill
- Use when user says "check skill", "skillcheck", or "validate SKILL.md"
- Use when reviewing a skill before publishing to a marketplace
- Use when debugging why a skill doesn't trigger correctly
- Use when onboarding a team to skill authoring standards
- Do NOT use for anti-slop detection, security scanning, or token analysis; use SkillCheck Pro for those
How It Works
Step 1: Parse
Read the target SKILL.md file and extract YAML frontmatter.
Step 2: Validate
Apply all Free tier checks in order:
| Category | Checks | What it catches |
|---|---|---|
| Structure (1.x) | Name format, description WHAT+WHEN, allowed-tools, categories, XML injection | Malformed frontmatter, missing fields |
| Body (2.x) | Line count, hardcoded paths, stale dates, empty sections, deprecated syntax, MCP tool qualification | Content quality issues |
$install
1-click copynpx skills add sickn33/antigravity-awesome-skills --skill skill-checkSafety assessment
★
Clarity score
How clear and easy to understand the SKILL.md instructions are, rated from 1 to 5.
5/ 5
excellentVery clear and well structured, with almost no room for misunderstanding.
◎
Actionability score
How directly an agent can act on the SKILL.md instructions, rated from 1 to 5.
5/ 5
very highHighly actionable with clear, concrete steps that an agent can follow directly.